Question 1144734
My guess is that none of the people involved are using algebra or you would have an answer by now!
Find the number of people using algebra.
"Using algebra " is known as a dangling modifier. It is unclear from the sentence what is being modified by the phrase.
I suspect you really wanted to say, " Use algebra to find the number of people splitting the tab."

Thank you for the comic relief!
BTW "Tab" here means the bill. They each want to pay a portion of the bill.